The fifth release of Apple's iPhone, called iPhone 4S, shows that looks and names can be deceiving, as Apple has once again raised the bar in the smartphone world.

It came late and with a different name than many expected. Some were anticipating a new hardware design (some case vendors went as far as to order cases made on rumored design changes), others a larger screen. More than a few expected something called iPhone 5.

But the fifth release of Apple 's iPhone, called iPhone 4S, shows that looks and names can be deceiving, as Apple has once again raised the bar in the smartphone world.

Physically, the 4S is nearly a dead ringer for the older iPhone 4, but changes under the hood set it apart enough that it could have been called iPhone 5.

There have been physical changes, but they aren't cosmetic. A new antenna design addresses notorious dropped-call problems that plagued iPhone 4. I couldn't get the 4S to lose a signal, no matter how I held it. Inside, there's an A5 processor, the same speedy chip that powers the iPad 2. Apple claims that the 4S up to twice as fast as the iPhone 4 and up to seven times faster in terms of graphics speed. IMy informal speed tests bear that out. Apps that used to take a few seconds to open now open immediately. The phone's camera, meanwhile, has been upgraded to 8 megapixels, can record 1080p video with image stabilization and has just about zero lag time between photos. Unless you need optical zoom, the iPhone 4S is good enough that you could toss your point-and-shoot into a drawer and forget all about it.

Then there's the software. The new iOS 5 powers the iPhone 4S (it's also available free to iPhone 3GS, iPod Touch, iPad and iPhone 4 users). There's a lot to like in this operating system, with existing features nicely polished. I was especially happy with improvements to notifications, which have gone from dismal on previous releases to state of the art and useful.

Notably, iOS introduces Apple's iCloud, which seamlessly synchronizes your information across computers, phones and tablets . While iCloud offers some Windows support, it's really geared toward tying all Apple devices together neatly. I've often said that if you control sync, you control the mobile world, and Apple is working very hard to create that seamless experience for the consumer cloud .

The real showstopper in the iPhone 4S is Siri. It is artificial intelligence from a company of the same name that Apple acquired last year (and that started as a DARPA project). Siri brings voice assistance and recognition to a new level, no training required. Outside of the realm of science fiction, there has never been such a smooth implementation of voice dictation, command, control, query and response in a handheld device. For many people, Siri brings to mind the kind of human-machine interaction we've all been expecting since we first saw HAL on the big screen in the 1968 movie 2001: A Space Odyssey. (For fun, ask Siri to open the pod bay doors for you.)

Siri parses your requests in natural language. You can ask for a weather report, or you can just say, "Siri, should I carry an umbrella today?" If you ask Siri to schedule a meeting and you already have a conflicting appointment on your calendar, Siri will let you know that and offer to schedule at a different time. Siri was impressive as a demo, but demos are carefully choreographed. I can tell you that Siri is just as impressive in actual use. Not that it's perfect. For now, it works best with English speakers, and its location-based services are tied to the U.S. for the most part. But Apple is cannily calling Siri a beta release, which makes its accuracy and response downright amazing. Nothing else I have used approaches its capabilities, and quite honestly, I wasn't expecting anything this good until much later this decade. But Siri is here now -- at last year's prices.

iPhone 4S is still on AT&T but also comes in Verizon and Sprint versions. I tested the AT&T model and found both voice and data quality to be excellent. Apple now finally offers a 64GB model, and you can even buy a carrier-unlocked, SIM-free version, but at an unsubsidized cost.

What's missing? While iOS 5 offers some new social integration with Twitter, other services, notably Facebook, remain as siloed apps. It would also be nice to see some widgets other than stocks and weather tied into notifications; that's something I'd like to see Apple open up to third parties. Some people would prefer an LTE phone or a bigger screen, and they will have to look elsewhere. And though the AT&T model claims to provide nearly 4G speeds, that's heavily dependent on what you call 4G (and a discussion beyond the scope of this column).

In short, this is a phone that resembles its predecessor in superficial ways but establishes a new baseline of smartphone performance. Whether they can match Apple in the tight integration of hardware and software is debatable, but that is what makes experiences like Siri a reality. And the 4S camera is going to dictate what's acceptable in a mobile phone.

A vocal contingent of Apple watchers has voiced their great disappointment that the company introduced something other than the anticipated iPhone 5. Consumers, though, have flocked to the device, with Apple reporting that it sold 4 million units on the first weekend.

Competitors will take note of what sets the iPhone 4 apart as well. Later this year, there will be new versions of Android and Windows Phone to challenge iOS. Competitors aren't about to cede this market to Apple, and I think we are all going to benefit from a rapid pace of innovation never seen before.